The proposed study will examine the effect of minority group membership and structural assimilation on the fertility of the foreign born in the United States. Two competing hypotheses provide the theoretical framework for the analysis. The "social characteristic" position states that assimilation is the process of equalization in the distributions of basic social position variables such as education, income, occupation, and place of residence. The "minority status" position argues that minority group membership has an additional, direct effect on social behavior. Using data from the one percent United States Public Use Samples for 1960 and 1970, this study will 1) clarify the underlying assumptions and develop criteria for evaluating the two major theoretical perspectives; 2) study the characteristics of the foreign born by country of origin to develop categories of monority groups; 3) utilize multivariate techniques for determining which hypothesis is more valid for different types of minority groups and for identifying the effects of differences in the process of assimilation on intergroup fertility differentials. The analysis will be concerned with current fertility as well as with cumulative fertility. The importance of understanding the effect of minority group membership on fertility for theories of assimilation and fertility is stressed.